Engineering Commons^™

Evaluating The Fate And Variability Of Soil Organic Carbon And Nitrogen Species Under Conservation Practices In The Raccoon River Watershed, Zhonglong Zhang, May Wu

Civil and Environmental Engineering Faculty Publications and Presentations

This study evaluates the fate and variability of soil organic carbon (SOC) stocks and nitrogen species using the latest version of the Soil and Water Assessment Tool– Carbon (SWAT-C) and assesses how conservation practices influence their dynamics in the Raccoon River Watershed (RRW). Dominated by intensive agricultural pro- duction, the RRW is a significant contributor of sediment and nutrient loads to local rivers and the Mississippi River. This SWAT-C model simulates the export of SOC and nitrogen species and evaluates their responses under varying management scenarios. Model calibration was performed for streamflow, sediment, nitrate, total nitrogen, and organic carbon with …

Research Progress On Generating Perfect Vortex Beams Based On Metasurfaces, Xiujuan Liu, Manna Gu, Ying Tian, Mingfeng Zheng, Bo Fang, Zhi Hong, Chee Leong Tan, Xufeng Jing

Electrical and Computer Engineering Faculty Publications and Presentations

This article reviews the latest advances in the generation and control of perfect vector beams using metasurfaces. In recent years, metasurfaces have garnered increasing interest due to their simple fabrication and easy integration. Perfect vortex beams (PVBs), as a type of vector beams, exhibit complex polarization states that require the superposition of multiple phases for their generation. The use of metasurfaces provides a compact platform for the generation of perfect vortex beams and enables more complex vortex beam control tasks, which are quite challenging for traditional optics. This paper begins by introducing the principle of perfect vortex beam generation using …

Scalar Source Localization Using Multi-Sensor Domains Of Dependence In Turbulent Channel Fow, Zejian You, Xiaowei Zhu, Qi Wang

Mechanical and Materials Engineering Faculty Publications and Presentations

Tracking hazardous events such as wildfire smoke, coastal oil spills, or chemical releases in natural environments is complicated by turbulent dispersion and molecular diffusion. This study presents a method to localize pollutant sources rapidly and accurately using infinite time-averaged measurements from a multi-sensor network, leveraging the duality between mean forward and adjoint scalar fields. The forward-adjoint duality states that measurements at the sensor (forward feld) are equal to the adjoint field at the source, providing crucial spatial information about the source. Consequently, the adjoint scalar fields can be interpreted as the domain of dependence for the sensor observations [1, 2]. …

Estimating Sediment Properties Using A New Source Level Function For Wind-Driven Underwater Sound Derived From Long-Term Archival Data, S Bruce Martin, Martin Siderius

Electrical and Computer Engineering Faculty Publications and Presentations

Wind-driven breaking waves generate the background sound throughout the ocean. An accurate source level for wind-driven breaking waves is needed for estimating the ambient sound levels needed for sound exposure modeling, environmental assessments, and assessing the detection performance of sonars. Previous models applied a constant roll-off of sound levels at -16 dB/decade at all wind speeds, and these models' source levels were flat at frequencies below ∼1000 Hz due to a lack of measurements. Here, we analyzed 16 long-term archival datasets with limited anthropogenic sound sources to estimate the wind-driven source level down to 100 Hz. We estimated the site-specific …

An Integrated Multivariate Econometric Modeling Framework For Risky Driving Behavior Related Crashes: Evaluating Crash Risk And Severity Across Zones, Pabitra Kumar Roy

Dissertations and Theses

Rapid advancements in crash modeling have yet to fully integrate multiple behavior-driven crash types and their severity outcomes within a single, scalable framework, specially in a way that captures the sequential nature of these behaviors where one risky action may amplify another. This study proposed an integrated multivariate econometric framework to jointly model crash frequency and severity outcomes for three major behaviorally driven crash types: alcohol-related, distraction-related, and aggressive-driving-related crashes. Specifically, using Oregon's 2022 census block group-level crash data, we propose an Integrated Multivariate Negative Binomial – Generalized Ordered Probit Fractional Split (IMNB–GOPFS) model to analyze these dimensions simultaneously while …

Leveraging High-Performance Cloud Computing To Model Underwater Acoustic Propagation And Scattering From Time-Evolving Rough Sea-Surfaces Using The Finite-Difference Time-Domain Method, James Alexander Higgins

Dissertations and Theses

This dissertation presents a two-dimensional (2D) Finite-difference Time-domain (FDTD) model for simulating underwater acoustic propagation and scattering from a one-dimensional (1D) time-evolving rough sea-surface. The techniques discussed are extendable to three spatial dimensions. Traditional acoustic modeling techniques often rely on a "frozen" sea-surface assumption, which proves inadequate for long-duration signals interacting with the time-evolving boundary at many different wave height displacements during its transit. To address this, a new FDTD update equation incorporating a variable subgrid is developed, significantly enhancing spatial accuracy at the boundary without increasing computational cost or compromising stability.

The model's accuracy is rigorously validated against established …

Lattice Thermal Transport Beyond The Quasiparticle Approximation: Nontrivial Spectral Competition Between Three- And Four-Phonon Interactions, Yi Xia

Mechanical and Materials Engineering Faculty Publications and Presentations

The breakdown of the quasiparticle approximation (QPA) for phonons in strongly anharmonic materials necessitates advanced first-principles frameworks for accurate lattice dynamics and thermal transport predictions. We develop a comprehensive beyond-quasiparticle approximation (BQPA) approach incorporating both three- (3ph) and four-phonon (4ph) interactions and apply it to investigate lattice thermal conductivity (κL) in MgO, PbTe, and AgCl – materials that span a broad spectrum of anharmonicity, from weak to severe anharmonic regimes with overdamped phonons. We reveal that while BQPA consistently increases κL relative to QPA due to phonon softening when considering only 3ph interactions, the inclusion of additional 4ph interactions hardens …

Concerted Rattling-Induced Strong Anharmonicity And Phonon Coherence Lead To Ultralow Glasslike Thermal Conductivity In Tlagte, Shantanu Semwal, Yi Xia, Chris Wolverton, Koushik Pal

Mechanical and Materials Engineering Faculty Publications and Presentations

Ordered crystalline compounds exhibiting ultralow and glass-like thermal conductivity are both fundamentally and technologically important, where phonon quasi-particles dominate their heat transport. Understanding the microscopic mechanisms that govern such unusual transport behavior is necessary to unravel the complex interplay of crystal structure, phonons, and collective excitations of these quasi-particles. Here, we use state-of-the-art first-principles calculations based on quantum density functional theory to investigate the origin of experimentally measured unusually low and glassy thermal conductivity in semiconducting TlAgTe that possesses disconnected chains of Tl atoms within its three-dimensional crystalline framework made up of distorted AgTe4 tetrahedra. Utilizing a unifying framework of …

Spike Timing Depended Plasticity Produces Unsupervised Learning Of Synergistic Muscle Feedback In A Synthetical Neural Network, Mark Allen Pupkiewicz

Dissertations and Theses

This study investigates how type Ia feedback from muscle spindles can be organized into groups representing agonistic muscle pairs through Spike Timing Dependent Plasticity (STDP). A single degree of freedom joint is actuated with four biologically modeled muscles forming two agonistic pairs. In order to emulate the sensory dynamics of biological muscle spindles, sensors in the model record the active length and velocity states of each muscle, the two primary factors eliciting type Ia afferent responses. In biological networks, synapses from Ia sensory neurons frequently activate interneurons representing agonistic muscle sources. This research investigates whether this organization can emerge in …

An Innovative Hdm Model For Assessing Renewable Heat Energy Resources In Utility Energy Systems, Mark Alan Ryan

Dissertations and Theses

Renewable Heat Energy projects exhibit numerous unique, complex, and often conflicting characteristics, including varying project sizes, diverse energy resources, stakeholder demands, and significant challenges in energy conversion applications. Traditionally, cash flow analysis and return on investment are the most widely recognized metrics for evaluating remote energy projects. However, numerous quantitative and qualitative factors influence the overall performance and success of Renewable Heat Energy System (RHES) projects. A comprehensive approach using advanced tools is essential for assessing the factors and criteria that significantly impact these projects.

This research investigates the key quantitative and qualitative factors that contribute to the successful implementation …

Expanderizing Higher-Order Random Walks, Vedat Levi Alev, Shravas Rao

Computer Science Faculty Publications and Presentations

We study a variant of the down-up (also known as the Glauber dynamics) and up-down walks over an 𝑛-partite simplicial complex, which we call expanderized higher-order random walks—where the sequence of updated coordinates corresponds to the sequence of vertices visited by a random walk over an auxiliary expander graph 𝐻. When 𝐻 is the clique with self-loops on [𝑛], this random walk reduces to the usual down-up walk, and when 𝐻 is the directed cycle on [𝑛], this random walk reduces to the well-known systematic scan Glauber dynamics. We show that whenever the usual higher-order random walks satisfy a log-Sobolev …

Favorability Mapping For Hydrothermal Power Resource Assessments Of The Great Basin, Usa, Stanley P. Mordensky, Erick R. Burns, John Lipor, Jacob Deangelo

Electrical and Computer Engineering Faculty Publications and Presentations

Highlights

• • The new approach to predict hydrothermal resource favorability for the U.S. Great Basin is a synthesis of modern data-driven machine learning improvements from the last several years and predicts 85 % of power-producing systems with operating power plants in the most favorable 10 % of the total area with over half of the power-producing systems (10 of the 19 exposed power-producing systems and 5 of the 9 hidden power-producing systems) in the 99th percentile.
• • The new hydrothermal favorability map predicts both hidden and exposed power-producing hydrothermal systems equally well.
• • The new hydrothermal favorability map preferentially predicts …

Realization Of Deterministic Quantum Circuits For Non-Deterministic Or Incompletely Specified Quantum State Machines, Manjith Kumar, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

In classical logic design, there are machine learning methods based on converting a set of input-output traces to non-deterministic automata that are then converted to deterministic automata and synthesized using logic gates. This approach has not yet been extended to quantum automata. In this paper, we present a method to convert a set of input-output traces to a non-deterministic automaton, which is then converted to an incompletely specified multi-output Boolean function. The existing logic synthesis approaches for designing quantum circuits are insufficient to handle incompletely specified functions. So, we present a novel algorithm to synthesize logic functions with don’t cares …

Jhtdb-Wind: A Web-Accessible Large-Eddy Simulation Database Of A Wind Farm With Virtual Sensor Querying, Xiaowei Zhu, Shuolin Xiao, Ghanesh Narasimhan, Luia A. Martinez-Tossas, Michael Schnaubelt, Gerard Lemson, Hanxun Yao, Alexander S. Szalay, Dennice F. Gayme, Charles Meneveau

Mechanical and Materials Engineering Faculty Publications and Presentations

This paper introduces JHTDB-wind (https://turbulence.idies.jhu.edu/datasets/windfarms), a publicly accessible database containing large-eddy simulation (LES) data from wind farms. Building on the framework of the Johns Hopkins Turbulence Database (JHTDB), which hosts direct numerical and some large-eddy simulation datasets of canonical turbulent flows, JHTDB-wind stores the full space-time (4D) history of the flow and provides users the ability to access and query the data via a web-based virtual sensor interface. The initial dataset comprises LES results from a large wind farm with 6 X 10 turbines, modeled using a filtered actuator line method, under conventionally neutral atmospheric conditions. This data comprises one …

Effect Of Pore Structure On Void Formation In Lotus Type Porous Cu/Solder Joints, Jin-Kwan Lee, Keun-Soo Kim, Jae-Ho Shin, Seung-Min Cho, Sung Yi, Sang-Wook Kim, Soong-Keun Hyun

Mechanical and Materials Engineering Faculty Publications and Presentations

Void formation in solder joints is a critical reliability challenge in high-power electronics, as it degrades thermal dissipation and mechanical integrity. This study investigates a novel structural approach to mitigate this issue. The influence of an uni-directional porous structure in lotus-type porous Cu (Louts Cu) on void formation in solder joints was investigated. All pores in lotus Cu were infiltrated with SAC305 (Sn–3.0Ag–0.5Cu) solder paste. Then reflow soldering was performed under three different atmospheric conditions: air, nitrogen, and vacuum. The microstructure and void fraction were characterized. The shear strength was evaluated. The shear strength of Louts Cu joint was slightly …

Field Canals Improvement Projects Duration Prediction: A Comparative Analysis Of Machine Learning Models, Hania Ghouse, Ukaegbu Chinonso Ishmael, Edgar Dario Obando-Paredes, Hashem Shafik Shakir, Ali Al-Bayaty

Electrical and Computer Engineering Faculty Publications and Presentations

There are several essential elements in project construction management to be studied appropriately, and priority to these elements, such as cost and duration, is predominantly interesting to be investigated. In this research, the duration of field canal improvement projects (DFCIP) was predicted using two relatively new machine learning (ML) models - the Multivariate Adaptive Regression Spline (MARS) and Extreme Learning Machine (ELM). The targeted DFCIP was calculated using other dependent parameters, such as the length of the pipe, years of construction, the geographical zone of the network, the supplied area with water, and finally the actual cost of the field …

Interfacial Gap Prediction In Laser Welding Of Pure Copper Overlap Joints Using Multiple Sensors., Hyeonhee Kim, Cheolhee Kim, Minjung Kang

Mechanical and Materials Engineering Faculty Publications and Presentations

In this study, a novel approach was proposed for predicting the interfacial gap in copper overlap joints by using deep learning and multi-sensor fusion. In this method, an image sensor, a spectrometer, and optical sensors tomography (OCT) sensors were used to develop and validate deep learning models under various gap conditions. The results revealed that the variation in melt pool dimensions, changes in keyhole behavior, intensity variations at specific wavelengths, and keyhole depth derived from the OCT data could be used to accurately predict the interfacial gap. Among the proposed models, a binary gap classification model achieved the highest accuracy …

First-Principles Theory Of Five-And Six-Phonon Scattering, Yi Xia

Mechanical and Materials Engineering Faculty Publications and Presentations

igher-order phonon scatterings beyond fourth order remain largely unexplored despite their potential importance in strongly anharmonic materials at elevated temperatures. We develop a theoretical formalism for first-principles calculation of five- and six-phonon scatterings using Green’s function techniques based on a diagrammatic formalism, and systematically investigate multi-phonon interactions in Si, MgO, and BaO from room temperature to near melting points. Our calculations reveal dramatically different material-dependent behaviors: while five- and six-phonon processes remain negligible in Si even at high temperatures, they become increasingly important in MgO near its melting point (3100 K) and in BaO at intermediate temperatures (1200 K). Most …

Framework And Methodology For Risk-Based Bridge And Tunnel Asset Management: Risk-Based Asset Ranking And Corridor Prioritization, David Y. Yang, Arash Khosravifar, Diane Moug, Avinash Unnikrishnan

Civil and Environmental Engineering Faculty Publications and Presentations

This report presents the results of Phase II of the project, "Framework and Methodology for Risk-based Bridge and Tunnel Asset Management". The research was carried out at Portland State University in collaboration with engineers and officials at the Oregon Department of Transportation (ODOT) and Federal Highway Administration (FHWA). Using the framework and methodology developed in Phase I of the project, the primary goal of Phase II is to showcase the practical application in risk-based asset management. In particular, the report includes the following two case studies: Case Study I — Weighted hazard scenarios for seismic risk assessment of Oregon Highway …

Wind Farm Dynamics Over A Diurnal Cycle: Analysis Of A Comprehensive Large-Eddy Simulation, Web-Services Accessible Dataset, Shuolin Xiao, Xiaowei Zhu, Ghanesh Narasimhan, Dennice F. Gayme, Charles Meneveau

Mechanical and Materials Engineering Faculty Publications and Presentations

The atmospheric boundary layer undergoes significant changes throughout a diurnal cycle, affecting wind turbine performance and wakes in wind farms. Wind farm large-eddy simulations (LES) under such conditions provide rich datasets to study the underlying dynamics and identify important trends. Here, we describe a comprehensive open dataset generated using LES of an eight-turbine wind farm consisting of four rows of two turbines. To avoid specifying either prescribed surface temperature or heat flux, a local one-dimensional soil heat conduction model is used with time-periodic solar surface heating, coupled to LES. After several days of low-resolution LES, an approximately time-periodic behavior is …

Model-Based Assessment Of Ocean Monitoring Temporal And Spatial Resolution Requirements For Acoustic Operations, William K. Stevens, Martin Siderius

Electrical and Computer Engineering Faculty Publications and Presentations

Understanding present and future ocean conditions is essential for the effective planning and execution of a wide range of naval and commercial acoustic operations. The four-dimensional structure of temperature and salinity}from the ocean surface to the seabed}is a critical factor influencing acoustic transmission properties. Modern numerical ocean modeling systems consist of three primary components: ocean observations, a numerical forecasting model, and a data assimilation system. Of the tens of millions of global ocean observations assimilated daily, the majority derive from satellite-based surface measurements. In stark contrast, subsurface water column measurements number only in the thousands per day. This disparity highlights …

Al-Driven Interfacial Gap Prediction In Overlapped Al/Cu Laser Weld Joint For Battery Applications, Hyeonhee Kim, Sanghoon Kang, Cheolhee Kim, Yong Hoon Jang, Minjung Kang

Mechanical and Materials Engineering Faculty Publications and Presentations

The battery tab-to-busbar welding process forms the primary electrical path in battery packs and is directly linked to both performance and safety. Variations in jig alignment, material tolerance, and forming quality can cause small interfacial gaps that lead to weak welds. An artificial intelligence (AI)-driven method was proposed in this study for predicting interfacial gaps in aluminum-copper overlap joints by integrating deep learning with multi-sensor data. A charge-coupled device (CCD) camera, spectrometer, and optical coherence tomography (OCT) sensors were employed to develop and validate deep learning models under varying gap conditions. The results revealed that the variation in melt-pool dimensions, …

Coupling The Parflow Integrated Hydrology Model Within The Nasa Land Information System: A Case Study Over The Upper Colorado River Basin, P.Eyman Abbaszadeh, Fadji Zaouna Maina, Chen Yang, Dan Rosen, Sujay Kumar, Matthew Rodell, Reed Maxwell

Civil and Environmental Engineering Faculty Publications and Presentations

Understanding, observing, and simulating Earth's water cycle is imperative for effective water resource management in the face of a changing climate. While NASA's Land Information System (LIS)/Noah-MP is widely used for land surface modeling, its ability to represent groundwater processes is limited. In contrast, the ParFlow hydrologic model explicitly simulates subsurface water movement. This study explores the effectiveness and usefulness of the newly coupled modeling framework, ParFlow-LIS/Noah-MP (PF-LIS/Noah-MP) over the Upper Colorado River Basin (UCRB). The framework integrates the strengths of both models to provide a physically based representation of surface and subsurface processes and their interactions. Unlike standalone LIS/Noah-MP, …

Development And Validation Of A Composite Digital Balance Score For Spinocerebellar Ataxia: A Prospective Study., James Mcnames, Vrutangkumar V. Shah, Hannah L. Casey, Kristen L. Sowalsky, Mahmoud El-Gohary, Delaram Safarpour, Patricia Carlson-Kuhta, Jeremy D. Schmahmann, Liana S. Rosenthal, Susan Perlman, Multiple Additional Authors

Electrical and Computer Engineering Faculty Publications and Presentations

Clinical trials in spinocerebellar ataxia are currently limited by the large sample sizes required by available clinical endpoints. We aimed to devise a digital composite measure of standing and walking balance using wearable inertial sensors that would require smaller sample sizes. The new score is called the Score of Integrated Balance in Ataxia (SIBA).

Calving As A Source Of Acute And Persistent Kinetic Energy To Enhance Submarine Melting Of Tidewater Glaciers, M. F. Shaya, J. D. Nash, E. C. Pettit, J. M. Amundson, R. H. Jackson, D. A. Sutherland, Dylan Winters

Electrical and Computer Engineering Faculty Publications and Presentations

Calving icebergs at tidewater glaciers release large amounts of potential energy. This energy—in principle—could be a source for submarine melting, which scales with near‐terminus water temperature and velocity. Because near‐terminus currents are challenging to observe or predict, submarine melt remains a key uncertainty in projecting tidewater glacier retreat and sea level rise. Here, we study one submarine calving event at Xeitl Sít’ (LeConte Glacier), Alaska, to explore the effect of calving on ice melt, using a suite of autonomously deployed instruments beneath, around, and downstream of the calving iceberg. Our measurements captured flows exceeding 5 m/s and demonstrate how potential …

Incorporating The Influence Of Vehicle Mix On Crash Frequency And Severity, Shahrior Pervaz, Manmohan Joshi, Tanmoy Bhowmik, Dewan Ashraful Parvez, Kai Wang, John N. Ivan, Naveen Eluru

Civil and Environmental Engineering Faculty Publications and Presentations

The current approaches for crash frequency and severity prediction in the Highway Safety Manual (HSM) do not employ vehicle mix information. In this research effort, we build advanced alternatives to HSM methods while incorporating vehicle mix information. Two model systems—(a) multivariate Poisson-lognormal model and (b) negative binomial-ordered probit fractional split model—are estimated by incorporating vehicle mix variables. The developed model systems can also capture the influence of observed and unobserved heterogeneity of different independent variables including vehicle mix variables. We estimate the models for three facility types including Urban Arterial 4-Lane Divided segments, Rural 3-Leg STOP-Controlled and Rural 4-Leg STOP-Controlled …

Freer Arrows And Why You Need Them In Haskell, Grant Vandomelen, Gan Shen, Lindsey Kupur, Yao Li

Computer Science Faculty Publications and Presentations

Freer monads are a useful structure commonly used in various domains due to their expressiveness. However, a known issue with freer monads is that they are not amenable to static analysis. This paper explores freer arrows, a relatively expressive structure that is amenable to static analysis. We propose several variants of freer arrows. We conduct a case study on choreographic programming to demonstrate the usefulness of freer arrows in Haskell.

Detection Of Two Anomalies Behind The Eastern Face Of The Menkaure Pyramid Using A Combination Of Non-Destructive Testing Techniques, Khalid Helal, Polina Pugacheva, Hussien Allam, Mohamed Fath-Elbab, Mohamed Sholqamy, Olga Popovych, Simon Schmid, Benedikt Maier, Alejandro Ramirez, Johannes Rupfle, Thomas Schumacher, Multiple Additional Authors

Civil and Environmental Engineering Faculty Publications and Presentations

The Menkaure Pyramid is the smallest of the three main pyramids on the Giza Plateau. Recently, the possibility of a second entrance to the Pyramid has been hypothesized by Van den Hoven [1], based on similarities between the polished granite blocks covering the Eastern face and the blocks around the main entrance on the Northern face. To test this hypothesis, measurement campaigns using three non-destructive techniques, Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR), and Ultrasonic Testing (UST), were carried out on the Eastern face of Menkaure Pyramid. ERT data was obtained from measurements of four long parallel profiles using …

Recovery Of Daily Water Levels In The Sacramento-San Joaquin Delta, 1915–2023, Serena B. Lee, Steven Dykstra, Reyna Gomez‐Sanchez, Cole Wilkenson, Ricardo Estrada, Nick Mcguire, David A. Jay, Stefan A. Talke

Civil and Environmental Engineering Faculty Publications and Presentations

This manuscript documents the data rescue, digitization, and quality assurance of archival daily maximum and minimum water levels at twenty-five sites within the Sacramento-San Joaquin Delta. The records encompass 1846 total unique years, where 915 years are newly digitized from the 1915–1985 era. The period of record for each gauge location varies from 40 to 109years (median=80 years). Quality assurance procedures and datum corrections were applied to both archival and digital records to generate a time series referenced to a common geocentric datum. Both riverine and coastal influences on mean sea level and great diurnal range are evident in the …

Seismic Fragility Analysis Of Above-Ground Liquid Storage Tanks, Pooyan Khajeh Shahzanian

Dissertations and Theses

Liquid storage tanks are critical infrastructure, serving as key storage facilities for various products. As the contents in these tanks are usually highly toxic and flammable, damage to these structures under earthquakes can cause severe consequences, including energy shortage, fire and explosion, and spilling and long-term environmental damages.

Although new liquid storage tanks are designed according to the updated seismic design codes, large numbers of existing storage tanks were built before modern seismic design codes and did not undergo necessary seismic retrofitting. Observations and reports from past earthquakes demonstrate that these older tanks can be highly vulnerable to seismic excitation. …